Features of FAT32, NTFS and exFAT file systems. What to do if data is lost Accessing files using fat

In FAT, file names are in 8.3 format and consist only of ASCII characters. VFAT has added support for long (up to 255 characters) file names. Long File Name, LFN) in UTF-16LE encoding, with LFNs stored concurrently with 8.3 names, retrospectively called SFNs. Short File Name). LFNs are case-insensitive when searching, however, unlike SFNs, which are stored in uppercase, LFNs preserve the case specified when the file was created.

FAT system structure

In the FAT file system, contiguous disk sectors are combined into units called clusters. The number of sectors in a cluster is equal to a power of two (see below). An integer number of clusters (at least one) are allocated to store file data, so, for example, if the file size is 40 bytes and the cluster size is 4 KB, only 1% of the space allocated for it will actually be occupied by file information. To avoid such situations, it is advisable to reduce the size of clusters, and to reduce the amount of address information and increase the speed of file operations, vice versa. In practice, some compromise is chosen. Since the disk capacity may well not be expressed in a whole number of clusters, usually at the end of the volume there are so-called. surplus sectors - a “remainder” of less than a cluster size that cannot be allocated by the OS for storing information.

The FAT32 volume space is logically divided into three contiguous areas:

• Reserved area. Contains service structures that belong to the partition boot record (Partition Boot Record - PBR, to distinguish it from the Master Boot Record - the master boot record of the disk; PBR is also often incorrectly called the boot sector) and are used when initializing the volume;
• An area of ​​a FAT table containing an array of index pointers ("cells") corresponding to the clusters of the data area. Typically there are two copies of the FAT table on the disk for reliability purposes;
• The data area where the actual contents of the files are recorded - that is, text text files, encoded image for picture files, digitized sound for audio files, etc. - as well as the so-called. metadata - information regarding the names of files and folders, their attributes, creation and modification times, sizes and placement on disk.

FAT12 and FAT16 also specifically allocate the root directory area. It has a fixed position (immediately after the last element of the FAT table) and a fixed size in sectors.

If a cluster belongs to a file, then the corresponding cell contains the number of the next cluster of the same file. If the cell corresponds to the last cluster of the file, then it contains a special value (FFFF 16 for FAT16). In this way, a chain of file clusters is built. Unused clusters in the table correspond to zeros. “Bad” clusters (which are excluded from processing, for example, due to the unreadability of the corresponding area of ​​the device) also correspond to a special code.

When a file is deleted, the first character of the name is replaced with a special code E5 16 and the chain of file clusters in the allocation table is reset to zero. Since information about the file size (which is located in the directory next to the file name) remains intact, if the file clusters were located sequentially on the disk and they were not overwritten by new information, it is possible to restore the deleted file.

Boot entry

The first FAT volume structure is called BPB. BIOS parameter block ) and is located in a reserved area, in sector zero. This structure contains information identifying the type of file system and the physical characteristics of the storage medium (floppy disk or hard disk partition).

BIOS Parameter Block

BPB was essentially absent from the FAT that served MS-DOS 1.x, since at that time there were only two different types of volumes - single-sided and double-sided five-inch 360 KB floppy disks, with the volume format determined by the first byte of the FAT area. BPB was introduced in MS-DOS 2.x in early 1983 as a required structure boot sector, by which the volume format should henceforth be determined; The old scheme of determining by the first byte of FAT has lost support. Also in MS-DOS 2.0, a hierarchy of files and folders was introduced (before this, all files were stored in the root directory).

The BPB structure in MS-DOS 2.x contained a 16-bit “total number of sectors” field, which meant that this version of FAT was fundamentally inapplicable for volumes larger than 2 16 = 65,536 sectors, that is, more than 32 MB with a standard sector size of 512 bytes. In MS-DOS 4.0 (1988), the above BPB field was expanded to 32 bits, which meant the theoretical volume size increased to 232 = 4,294,967,296 sectors, or 2 TB with a 512-byte sector.

The next modification of BPB appeared with Windows 95 OSR2, which introduced FAT32 (in August 1996). The two-gigabyte limit on volume size has been removed; a FAT32 volume can theoretically be up to 8 TB in size. However, the size of each individual file cannot exceed 4 GB. BIOS Parameter Block FAT32, for the purpose of compatibility with earlier versions of FAT, repeats the BPB FAT16 up to and including the BPB_TotSec32 field, followed by differences.

The FAT32 "boot sector" is actually three 512-byte sectors - sectors 0, 1 and 2. Each of them contains the 0xAA55 signature at address 0x1FE, that is, in the last two bytes if the sector size is 512 bytes. If the sector size is more than 512 bytes, then the signature is contained both at address 0x1FE and in the last two bytes of the zero sector, that is, it is duplicated.

FSInfo

The boot record of a FAT32 partition contains a structure called FSInfo, used to store the number of free clusters on the volume. FSInfo, as a rule, occupies sector 1 (see the BPB_FSInfo field) and has the following structure (addresses relative to the beginning of the sector):

• FSI_LeadSig. The 4-byte signature 0x41615252 indicates that the sector is used for the FSInfo structure.
• FSI_Reserved1. The interval from the 4th to the 483rd byte of the sector, inclusive, is reset to zero.
• FSI_StrucSig. Another signature is located at address 0x1E4 and contains the value 0x61417272.
• FSI_Free_Count. The four-byte field at address 0x1E8 contains the last value of the number of free clusters on the volume known to the system. A value of 0xFFFFFFFF means that the number of free clusters is unknown and must be calculated.
• FSI_Nxt_Free. The four-byte field at address 0x1EC contains the cluster number from which the search for free clusters should begin in the table of index pointers. Typically this field contains the number of the last FAT cluster allocated to store the file. The value 0xFFFFFFFF means that the search for a free cluster should be carried out from the very beginning of the FAT table, that is, from the second cluster.
• FSI_Reserved2. Reserved 12-byte field at address 0x1F0.
• FSI_TrailSig. Signature 0xAA550000 - last 4 bytes of the FSInfo sector.

The point of introducing FSInfo is to optimize system operation, since in FAT32 the table of index pointers can be significant and scanning it byte-by-byte can take considerable time. However, the values ​​of the FSI_Free_Count and FSI_Nxt_Free fields may not be correct and should be checked for adequacy. In addition, they are not even updated in the FSInfo backup, which is usually located in sector 7.

Determining the FAT volume type

The determination of the FAT type of a volume (that is, the choice between FAT12, FAT16 and FAT32) is made by the OS based on the number of clusters in the volume, which in turn is determined from the BPB fields. First of all, the number of sectors of the root directory is calculated:

RootDirSectors = (BPB_RootEntCnt * 32) / BPB_BytsPerSec

DataSec = TotSec - (BPB_ResvdSecCnt + (BPB_NumFATs * FATSz) + RootDirSectors)

Finally, the number of data area clusters is determined:

CountofClusters = DataSec / BPB_SecPerClus

Based on the number of clusters, there is a clear correspondence with the file system:

• CountofClusters< 4085 - FAT12
• CountofClusters = 4085 ÷ 65524 - FAT16
• CountofClusters > 65524 - FAT32

According to the official specification, this is the only valid way to determine the FAT type. Artificially creating a volume that violates the specified compliance rules will result in Windows processing it incorrectly. However, it is recommended to avoid CountofClusters values ​​close to critical (4085 and 65525) in order to correctly determine the file system type by any, often incorrectly written, drivers.

Over time, FAT began to be widely used in various devices ah for compatibility between DOS, Windows, OS/2, Linux. Microsoft has shown no intention of forcing them to license [ specify] .

In February 2009, Microsoft sued TomTom, a manufacturer of Linux-based car navigation systems, accusing it of patent infringement.

Notes

1. http://cd.textfiles.com/megademo2/INFO/OS2_HPFS.TXT
2. www.microsoft.com/mscorp/ip/tech/fathist.asp at archive.org
3. Microsoft Extensible Firmware Initiative FAT32 File System Specification 1.03. Microsoft (December 6, 2000). - Document format Microsoft Word, 268 KB. Archived
4. What About VFAT? . TechNet Archive. Microsoft (October 15, 1999). Archived from the original on August 22, 2011. Retrieved April 5, 2010.
5. The VFAT file system extension should not be confused with the file system driver of the same name, which appeared in Windows for Workgroups 3.11 and is designed to process calls to MS-DOS functions (INT 21h) in protected mode (see: KB126746: Windows for Workgroups Version History. VERSION 3.11 → Non-Network Features. Microsoft (November 14, 2003). Archived from the original on August 22, 2011. Retrieved April 5, 2010.)
6. Federal Patent Court declares FAT patent of Microsoft null and void (English). heise online. Heise Zeitschriften Verlag (2 March 2007). Archived
7. Brian Kahin. Microsoft Roils the World with FAT Patents. The Huffington Post (March 10, 2009). Archived from the original on August 22, 2011. Retrieved March 10, 2009.
8. Ryan Paul. Microsoft suit over FAT patents could open OSS Pandora's Box (English). Ars Technica. Condé Nast Publications (February 25, 2009). Archived
9. Glyn Moody.(English) . ComputerworldUK. IDG (5 March 2009). Archived from the original on August 22, 2011. Retrieved March 9, 2009.
10. Steven J. Vaughan-Nichols. Linux companies sign Microsoft patent protection pacts (English). Computerworld Blogs. IDG (5 March 2009). Archived from the original on August 22, 2011. Retrieved March 9, 2009.
11. Erica Ogg. TomTom countersues Microsoft in patent dispute. CNet (March 19, 2009). Archived from the original on August 22, 2011. Retrieved March 20, 2009.

Links

• ECMA-107 (English) FAT standard

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Each of us at least once in our lives formatted a flash drive, SD card, external or internal hard drive and probably remembers that before starting to format any of the above devices, the Windows operating system always asks the question - which file system do you want to format your device into: FAT32, NTFS or exFAT?

Of course, most users do not know the difference between them, and usually choose the default option. And all because Windows, asking this question, does not explain the difference between them. In this article we will try to explain it to you in a clear language and tell you how the FAT32 file system differs from NTFS and exFAT.

FAT32 is the oldest of the file systems under consideration and is most often used on portable flash drives - flash drives or SD cards.

NTFS used by Windows as the main file system for the disk on which this operating system is installed, and it also works great for other built-in disks and partitions hard drive computer running Windows.

exFAT is a more modern analogue of the outdated FAT32 system and is supported by more devices than NTFS, but still not as many as the “classic” FAT32.

Now let's take a closer look at each of these file systems.

File system FAT32

FAT32 is the oldest file system discussed in this article. It began to be actively used starting from Windows 95 and replaced an even more outdated system - FAT16.

The great age of this file system has its advantages and disadvantages.

The advantages in this case include the fact that FAT32 has become a kind of standard and is still used by default in all removable media. If you buy a flash drive or SD card today, the FAT32 file system will be installed on it from the factory. This was done primarily so that your removable media can support not only modern computers and gadgets, but also old devices and game consoles that have USB port and can only work with the FAT32 file system.

However, due to the age of this system, it also has some disadvantages, the main of which is the limitation on the size of the file and the entire volume. Each individual file on this file system cannot be larger than 4 gigabytes, and the entire FAT32 partition cannot be larger than 8 terabytes.

And if you can still come to terms with the second disadvantage (so far few people use drives larger than 8TB), then the limitation on file size is a rather serious disadvantage - most videos are in high quality now they no longer fit into the 4GB size, especially if they are in the modern 4K format.

However, for now, this file system is still quite suitable for portable devices (like flash drives and SD cards, which contain many small files), but it is no longer suitable for a computer hard drive. First of all, it lacks some of the security features found in the more modern NTFS file system, and partly because of this, you can no longer install a modern version of Windows on a FAT32 drive; you will need to reformat it to NTFS.

FAT32 compatible

Devices with the FAT32 file system are the most universal and are compatible with all versions of Windows, Mac OS, Linux operating systems, any game consoles and, in general, almost everything that has a USB port.

Limitations of FAT32

The main disadvantage of this file system is the limitations on file and volume sizes - maximum size The file cannot exceed 4 GB, and the maximum partition size is limited to 8 TB.

Application of FAT32

The main area of ​​use of this file system is external data storage devices, which are not intended to store large files and which require maximum compatibility with as many different devices as possible.

File system NTFS

NTFS- this is a more modern and technological file system, as evidenced by even the decoding of the abbreviation of its name -" new technology file system". Most of all, the Windows operating system loves it, which in general is not surprising - after all, both of them were developed by Microsoft.

Starting with the version of the operating system from Microsoft called XP, in which the NTFS system first became standard, with Windows installation the dialog box will definitely ask you to format the system partition into this particular file system. At this point, it's believed that you theoretically won't have to worry about the limitations of the NTFS file system for many years to come.

In addition to the absence of serious restrictions on file and partition size, NTFS has several additional advantages, such as: support for file access rights (to increase data security), change logging (to restore the file structure in case of failure), encryption, disk quotas, hard links , and other modern features that make NTFS ideal for a system drive.

That is why the partition of your disk on which the Windows operating system is installed must be formatted in NTFS. If you are going to install programs on other partitions of the same disk or other hard drives, they must also have an appropriate file system.

Unfortunately, NTFS is not compatible with most other operating systems, as it was designed to meet the requirements of Windows OS. All versions of Microsoft's operating system, from XP to today's latest Windows 10, work perfectly with it, but other operating systems have significant limitations when working with it.

For example, Mac OS can only read data from NTFS drives, but cannot write to them. Some rare Linux distributions may have the ability to write to NTFS disks, but most are still limited to reading information only. None of the Playstation versions can work with NTFS, nor can Microsoft's Xbox 360, and only the new Xbox One supports this file system.

NTFS Compatibility

This file system works great with everyone latest versions operating room Windows systems Since XP, it has recording limitations on Mac OS and Linux, and does not work with most other devices, with the possible exception of the Xbox One.

NTFS Limitations

Limitations on the size of files or partitions in NTFS should not be limited for a long time, so we can say that at the moment there are none.

Using NTFS

The use of this file system is reasonable only for hard drives and SSDs on which the Windows operating system is installed, since only with it this format reveals all its advantages.

exFAT file system

exFAT was first introduced in 2008 and is the most modern of the file systems discussed in this article; its support was added to Windows starting with version XP through OS updates.

The exFAT file system was created and optimized for use on external drives- flash drives, SD cards and external hard drives, and is designed to replace the outdated FAT32 system. It is the lightest and simplest file system due to the absence of various specialized features inherent in NTFS, as well as the almost complete absence of file and partition size restrictions that FAT32 has.

Also, exFAT has better compatibility with various operating systems than NTFS, and devices with it are perfectly readable and rewritten on both Windows and Mac OS, and on Linux (subject to installing some software).

Since exFAT is supported by the operating system Mac system OS by default, it will probably be supported by most other modern devices that Apple devices work with, for example, digital cameras.

Modern versions of gaming consoles such as Xbox One and Playstation 4 also support exFAT devices, unlike their previous versions (Xbox 360 and Playstation 3).

exFAT compatible

exFAT works great with all modern Windows versions(starting from XP) and Mac OS. To work with Linux, you will need to install additional software. This file system supports many more different devices than NTFS, but some of them (mostly older versions) can still only work with FAT32.

exFAT Limitations

Also, as in the case of NTFS, there are still no realistic restrictions on the size of a file or partition in the exFAT system.

Application of exFAT

This file system is perfect for use on various removable media, the file size of which can exceed 4 GB (external hard drives, large flash drives). If all the devices you work with are modern, you can easily abandon FAT32 on removable drives in favor of exFAT.

To summarize, we can draw the following conclusions: NTFS is great for a Windows system hard drive, exFAT is better used on removable storage media, and FAT32 should only be used if you want to achieve maximum compatibility with the wide variety of your devices.

A file system provides a way to organize a disk. It defines how data is stored on disk and what types of information can be attached to files—file names, permissions, and other attributes.

Windows supports three different file systems. NTFS– the most modern file system. Windows uses NTFS for its system disk and, by default, for most fixed disks. FAT32 is an older file system that is not as efficient as NTFS and does not support a large set of features, but provides greater compatibility with other operating systems. exFAT is a modern replacement for FAT32 and is supported by more devices and operating systems than NTFS - but it is not as widespread as FAT32.

NT File System (NTFS)

NTFS is modern file system, which Windows prefers to use by default. During installation, Windows formats system disk to the NTFS file system format. NTFS has such huge file size and partition size limits that you are unlikely to ever encounter them. NTFS first appeared in the consumer version of Windows XP, although it originally debuted in Windows NT.

NTFS is packed with modern features not available with FAT32 and exFAT. NTFS supports file permissions for security, a change log that can help you quickly recover from errors if your computer crashes, shadow copies for backup copies, encryption, disk quota restrictions, hard links and various other features. Many of them are critical to the operating system disk, especially file permissions.

System Windows partition must be in NTFS format. If you have additional disk along with Windows and you plan to install programs on it, it is better to also format it in NTFS. And, if you have any drives for which compatibility isn't an issue—because you know you'll be using them on Windows systems—feel free to choose NTFS.

Despite its advantages, NTFS lacks compatibility. It will work with all the latest versions of Windows - up to Windows XP - but it has limited compatibility with other operating systems. By default, Mac OS X can only read NTFS drives, but not write data. Some Linux distributions may include support for NTFS writing, but others may be read-only. None of the Sony PlayStation consoles support NTFS. Even Microsoft's own Xbox 360 console cannot read NTFS drives other than the Xbox One. Other devices are even less likely to support NTFS.

Compatibility: Works with all versions of Windows, but is read-only on Mac, and may be read-only on some Linux distributions. Other devices, with the exception of the Microsoft Xbox One, will likely not support NTFS.

Restrictions: Unrealistic file and partition size limits.

Ideal use: Use this for your Windows system drive and other internal drives that will only be used with Windows.

File Allocation Table 32 (FAT32)

FAT32 is the oldest of the three file systems available in Windows. It was introduced in Windows 95, and replaced the old FAT16 file system used in MS-DOS and Windows 3.

The age of the FAT32 file system has its advantages and disadvantages. The big advantages are that FAT32 is the de facto standard. Flash drives included in the packaging often have the FAT32 file system for maximum compatibility not only with modern computers, but also other devices, such as game consoles and anything with a USB port.

However, its limitations are also related to age. Individual files on a FAT32 drive cannot be larger than 4 GB - this is the maximum. The FAT32 partition must also be smaller than 8 TB. These are the boundaries that modern user devices have come close to.

FAT32 is suitable for USB flash drives and other external media - especially if you know you'll be using them on another non-Windows PC. This file system lacks the permissions and other security features built into the more modern NTFS file system. Additionally, modern versions of Windows can no longer be installed on a drive formatted with FAT32; they must be installed on drives formatted with NTFS.

Compatibility: Works with all versions of Windows, Mac and Linux, game consoles, and almost any device with a USB port.

Restrictions: Maximum file size is 4 GB, maximum partition size is 8 TB.

Ideal use: Use on removable drives where you need maximum compatibility with a wide range of devices unless you are using 4GB or larger files.

Extended File Allocation Table (exFAT)

exFAT file system was introduced in 2006 and was added to older versions of Windows with updates for Windows XP and Windows Vista. exFAT is Flash-optimized file system– designed to maintain FAT32 compatibility, but without the extra features of NTFS and without the limitations of FAT32.

Like NTFS, exFAT has very large file and partition size limits, allowing you to store files much larger than the 4 GB allowed by FAT32.

Although exFAT does not exactly match the compatibility of FAT32, it is more widely compatible than NTFS. Even Mac OS offers full exFAT support for reading and writing. exFAT disks can be accessed on Linux after installing the appropriate software. It's a little more complicated with other devices: PlayStation 4 supports exFAT; PlayStation 3 does not support; Xbox One supports it, but Xbox 360 does not.

Compatibility: works with all versions of Windows and modern ones Mac versions X, but requires additional software on Linux. More devices support exFAT, but some - especially older ones - only work with FAT32.

Restrictions: Unrealistic file and partition size limits.

Ideal use: Use it when you need to store large files and when you need wide compatibility. Assuming every device you want to use supports exFAT, you should format your device with exFAT instead of FAT32.

NTFS is ideal for internal drives, while exFAT is usually ideal for flash drives. However, sometimes you may need to format external drive using FAT32 if exFAT is not supported on the device you want to use it with.

There are many ways to store information and programs on a hard drive. A very well-known system is that saves various information in the form of files, grouping them into folders and assigning a unique . However, few people have thought about how the physical storage of information on a medium actually occurs.

In order for information to be stored on a physical medium, it must be prepared for use in a computer operating system. The operating system allocates free disk space to save information. To do this, you need to divide the disk into small containers - sectors. Low-level disk formatting allocates a specific size to each sector. The operating system groups these sectors into clusters. Top-level formatting sets all clusters to the same size, typically ranging from 2 to 16 sectors. Subsequently, one or more clusters are allocated for each file. The cluster size depends on the operating system, disk capacity, and the required operating speed.

In addition to the area for storing files on the disk, there are areas necessary for the operation of the operating system. These areas are designed to store boot information and information to map file addresses to physical locations on disk. The boot area is used to start the operating system. After BIOS boot The boot area of ​​the disk is read and executed to start the operating system.

File system FAT

The FAT file system appeared along with the operating system Microsoft system DOS, after which it was improved several times. It has FAT12, FAT16 and FAT32 versions. The name FAT itself comes from the file system's use of a kind of database in the form of a “File Allocation Table”, which contains an entry for each cluster on the disk. Version numbers refer to the number of bits used in the element numbers in the table. Therefore, the file system has a limit on the disk size it can support. In 1987, it did not support disks larger than 32 MB. WITH the advent of Windows 95 out new version FAT32 file system with theoretical support for disks up to 2 TB. Persistent problems with supporting large disk sizes arise from the fixed number of elements, limited by the number of bits used in determining the location of the cluster. For example, the FAT16 version does not support more than 2 16 or 65536 clusters. The number of sectors in a cluster is also limited.

Another problem with large disks was the inability to use the huge space allocated for small files. Due to the fact that the number of clusters is limited, their size was increased so that the entire disk capacity could be covered. This results in inefficient use of storage space for most files that are not a multiple of the cluster size. For example, FAT32 allocates 16 KB clusters for disk partitions ranging from 16 to 32 GB. To store a 20 KB file, you will need two 16 KB clusters, which will take up 32 KB of disk space. 1 KB files take up 16 KB of disk space. Thus, on average, 30-40% of the disk capacity is wasted for storing small files. Partitioning the disk into small partitions allows you to reduce the cluster size, but is not used in practice for disks with a capacity of more than 200 GB.

File fragmentation is also not a small file system problem. Since placing a file may require multiple clusters, which may not be physically located sequentially, the time it takes to read it slows down programs. Therefore, the need for .

File system NTFS

In the early 90s, Microsoft began developing entirely new software designed for environments that were more resource-intensive than the average home user. For the needs of business and industry, the resources provided by DOS-based Windows operating systems have become insufficient. Microsoft Corporation together with IBM worked on the OS/2 operating system with the HPFS (High Performance File System– high efficiency file system). Corporate development did not bring success and soon each company again went its own way. Microsoft developed various versions of the Windows NT operating system, on which Windows 2000 and Windows XP are built. Each of them uses its own version of the NTFS file system, which continues to evolve.

NTFS (New Technology File System) is the standard file system for Windows NT-based operating systems. It was developed to replace FAT. NTFS is the most flexible compared to FAT. Its system areas store mostly files rather than fixed structures like FAT, which allows them to be changed, expanded or moved during use. A simple example is the Master File Table (MFT) - “master file table”. MFT is a kind of database with various information about files on disk. Small files (1 KB or less) can be stored directly in MFT. For large files, NTFS allocates clusters, but unlike FAT, the cluster size usually does not exceed 4 KB, and the built-in compression method eliminates problems with unused space allocated for files. You can also use .

The NTFS file system is designed for a multi-user environment and has built-in security mechanisms and access rights. For example, the Windows 2000 and Windows XP operating systems (except for the Home edition) allow you to set access permissions to separate files and encrypt them. However, the high level of security makes it difficult for ordinary users to work with a computer. You need to be extremely careful when setting passwords and file permissions to avoid losing important data.

In addition to all other tasks, it fulfills its main purpose - organizes work with data according to a certain structure. The file system is used for these purposes. What FS is and what it can be, as well as other information about it will be presented below.

General description

The file system is a part of the operating system that is responsible for placing, storing, deleting information on media, providing users and applications with this information, and also providing it safe use. In addition, it helps in data recovery in case of hardware or software failure. This is why the file system is so important. What is FS and what can it be? There are several types:

For hard drives, that is, random access devices;

For magnetic tapes, that is, devices with sequential access;

For optical media;

Virtual systems;

Network systems.5

The logical unit of data storage in a file system is a file, that is, an ordered collection of data that has a specific name. All data used by the operating system is presented in the form of files: programs, images, texts, music, videos, as well as drivers, libraries, etc. Each such element has a name, type, extension, attributes, and size. So, now you know, the File System is a collection of such elements, as well as ways to work with them. Depending on the form in which it is used and what principles are applicable to it, several main types of FS can be distinguished.

Software approach

So, if we are considering a file system (what it is and how to work with it), then it should be noted that this is a multi-level structure, at its top level there is a file system switch that provides an interface between the system and a specific application. It converts requests to files into a format that is perceived by the next level - drivers. They, in turn, contact the drivers specific devices, which store the necessary information.

U client-server applications FS performance requirements are quite high. Modern systems are designed to provide efficient access, support for large-volume media, protect data from unauthorized access, and maintain the integrity of information.

File system FAT

This type was developed back in 1977 by Bill Gates and Mark McDonald. It was originally used in OS 86-DOS. If we talk about what the FAT file system is, it is worth noting that initially it was not capable of supporting hard drives, but only worked with flexible media up to 1 megabyte. Now this limitation is no longer relevant, and this FS was used by Microsoft for MS-DOS 1.0 and subsequent versions. FAT uses certain file naming conventions:

The name must begin with a letter or number, and the name itself can contain any ASCII character, in addition to a space and special elements;

The name must be no more than 8 characters long, followed by a dot, and then the extension, which consists of three letters;

File names can use any case and are not distinguished or preserved.

Since FAT was originally designed for the single-user DOS operating system, it did not provide for storing data about the owner or access permissions. At the moment, this file system is the most widespread; most people support it to one degree or another. Its versatility makes it possible to use it on volumes that work with different operating systems. This is a simple FS that is not capable of preventing file corruption due to incorrect shutdown of the computer. Operating systems operating on its basis include special utilities that check the structure and correct file inconsistencies.

File system NTFS

This FS is the most preferable for working with Windows NT OS, since it was developed specifically for it. The OS includes a convert utility that converts FAT and HPFS volumes to NTFS volumes. If we talk about what the NTFS file system is, it is worth noting that it has significantly expanded the capabilities of access control to certain directories and files, introduced many attributes, implemented dynamic file compression tools, fault tolerance, and supports the requirements of the POSIX standard. In this FS you can use names up to 255 characters long, and the short name in it is generated in the same way as in VFAT. Understanding what the NTFS file system is, it is worth noting that if the operating system fails, it is capable of recovering itself, so the disk volume will remain accessible and the directory structure will not be affected.

Features of NTFS

On an NTFS volume, each file is represented by an entry in the MFT table. The first 16 table entries are reserved by the file system itself to store special information. The very first entry describes the file table itself. When the first record is destroyed, the second is read to find a mirror MFT file where the first record is identical to the main table. A copy of the boot file is located in the logical center of the disk. The third entry in the table contains a log file that is used for data recovery. The seventeenth and subsequent entries in the file table contain information about the files and directories that are on the hard drive.

The transaction log contains the full set of operations that change the structure of the volume, including file creation operations, as well as any commands that affect the directory structure. The transaction log is designed to recover NTFS from a system failure. The root directory entry contains a list of directories and files that are located in the root directory.

Features of EFS

The Encrypting File System (EFS) is a Windows component, with which information on the hard drive can be saved in an encrypted format. Encryption has become the strongest protection that this operating system can offer. In this case, encryption for the user is a fairly simple action; it only requires checking a box in the properties of the folder or file. You can specify who can read such files. Encryption occurs when files are closed, and when they are opened, they are automatically ready for use.

RAW Features

Devices designed for storing data are the most vulnerable components, which are most often subject to damage not only physically, but also logically. Certain hardware problems can be fatal, while others have solutions. Sometimes users have a question: “What is the RAW file system?”

As you know, in order to write any information to a hard drive or flash drive, the drive must have a FS. The most common are FAT and NTFS. And RAW is not even a file system as we usually imagine it to be. In fact, this is a logical error already installed system, that is, its virtual absence for Windows. Most often, RAW is associated with the destruction of the file system structure. After this, the OS does not simply access the data, but also does not display technical information by equipment.

Features of UDF

Universal disk format(UDF) is designed to replace CDFS and add support for DVD-ROM devices. If we talk about what it is, this is a new implementation old version for which it meets the requirements. It is characterized by certain features:

File names can be up to 255 characters long;

The name can be lowercase or uppercase;

The maximum path length is 1023 characters.

Starting with Windows XP, this file system supports reading and writing.

This FS is used for flash drives that are supposed to be used when working with different computers, running different operating systems, in particular Windows and Linux. It was EXFAT that became the “bridge” between them, since it is capable of working with data received from the OS, each of which has its own file system. What it is and how it works will become clear in practice.

Conclusions

As is clear from the above, each operating system uses certain file systems. They are intended for storing ordered data structures on physical storage media. If you suddenly have a question while using your computer about what a final file system is, then it is quite possible that when you tried to copy a certain file to the media, you received a message about exceeding the allowed size. That is why it is necessary to know in which FS what file size is considered acceptable, so that you do not encounter problems when transferring information.